updateJustTime function
Given a DateTime this will replace just the time portion leaving the date unchanged
Implementation
DateTime updateJustTime(TimeOfDay newTime, DateTime originalDateTime) {
return DateTime(
originalDateTime.year, // year
originalDateTime.month, // month
originalDateTime.day, // day
newTime.hour, // hour
newTime.minute, // minute
0, // second
0, // millisecond
0, // microsecond
);
}